Author |
Message |
PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
|
Posted: Sat Feb 15, 2014 6:24 am Post subject:
How does this potentiometer work ? Subject description: a stereopot with 2x 5 connections |
|
|
I'm retracing an old passive tonecontrol circuit I once took out of an amplifier (I think it was one of those radio/tapedeck/record player combos), and there
is a potentiometer on the PCB which has 2x 5 connections. I think it's used as a volume control with loudness but I'm wondering how the potentiometer
works. I tried to measure it and it seems like it has fixed resistors build in on each end, but I'd have to desolder it to be sure. So maybe someone knows
and another question,. what's the value of the capacitor on the 3rd pic; 150nF/100V, 100nF/150V, 150pF/100V, 100pF/150V ? (I don't think it's one of the last 2 options)
Description: |
|
Filesize: |
71.21 KB |
Viewed: |
237 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
Description: |
|
Filesize: |
82.32 KB |
Viewed: |
221 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
Description: |
|
Filesize: |
88.76 KB |
Viewed: |
227 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
Description: |
|
Filesize: |
47.56 KB |
Viewed: |
287 Time(s) |
This image has been reduced to fit the page. Click on it to enlarge. |
|
_________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
|
Back to top
|
|
|
blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
|
Posted: Sat Feb 15, 2014 10:04 am Post subject:
|
|
|
sometimes tone control pots would have fixed taps ... and i've seen ganged pots being used too ... maybe google Baxandall ... if I spelled that correctly ... _________________ Jan
also .. could someone please turn down the thermostat a bit.
|
|
Back to top
|
|
|
PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
|
|
Back to top
|
|
|
analog_backlash
Joined: Sep 04, 2012 Posts: 393 Location: Aldershot, UK
Audio files: 21
|
Posted: Sat Feb 15, 2014 5:11 pm Post subject:
Re: How does this potentiometer work ? Subject description: a stereopot with 2x 5 connections |
|
|
My guess (for what it's worth) would be 150nF/100V, as I've only seen that type of capacitor with DC ratings of 63V, 100V, 250V, 400V... and they're usually in the nF range. I think that they're the SilverCap™ type of metallized polyester film and I really dislike them as it's so easy to break the contact wires off
Gary
accidental edit by PHOBoS (oops I have to get used to these new buttons)
No worries - I wondered what had happened there Last edited by analog_backlash on Sun Feb 16, 2014 4:19 am; edited 1 time in total |
|
Back to top
|
|
|
delayed
Joined: Jun 24, 2008 Posts: 130 Location: TN
|
Posted: Sat Feb 15, 2014 6:04 pm Post subject:
|
|
|
Fender used center tapped pots in some of their designs also. |
|
Back to top
|
|
|
PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
|
Posted: Sat Feb 15, 2014 6:45 pm Post subject:
|
|
|
PHOBoS wrote: | My guess (for what it's worth) would be 150nF/100V, as I've only seen that type of capacitor with DC ratings of 63V, 100V, 250V, 400V... and they're usually in the nF range. I think that they're the SilverCap™ type of metallized polyester film and I really dislike them as it's so easy to break the contact wires off |
Thanks Gary, 150nF was my guess too. And you're correct about those wires breaking off. Before ordering online I always went to the shop
with a list of parts which I would hand over. And I never really knew what i would end up with. Always hated it when I got those caps. Didn't really
have anything in stock back then (apart from some desoldered stuff) so it really sucked when a contact broke off.
delayed wrote: | Fender used center tapped pots in some of their designs also. |
Thanks, those were the magic words.
I found this:
Quote: | Another common use for tapped controls was on a specially compensated volume control, called a Loudness control. In general, it allowed increased bass response with decreasing volume control settings, to compensate for the human ear's nonlinear response with respect to sound pressure level (Fletcher-Munsen curves). You'll find a button on the front panel of your home stereo to engage the additinal circuit components attached to this "loudness tap" on the volume control. There do exist multiple tapped volume pots for precision loudness tracking, but the normally encountered single tapped version has a tap at the physical center of the resistance track, which is at 10%/90% electrical resistance point on the audio taper volume pot. |
here _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
|
Back to top
|
|
|
|